Saturday, June 14, 2008

Turf and Landscape - Crabgrass

Warm weather is upon us and crabgrass is growing rapidly now. The following is information on crabgrass control.

With the recent rainfall and warm weather, crabgrass (smooth crabgrass, Digitaria ischaemum; large crabgrass, Digitaria sanguinalis) growth can be rapid in turf and landscape beds where preemergence grass herbicides were not applied or where residual herbicide barriers are starting to break down. Ideally, postemergence herbicides should be applied when crabgrass seedlings are still small. In cool season turfgrass, if crabgrass seedlings have not started to tiller, dithiopyr (Dimension) can be used and will provide additional preemergence activity for late germinating crabgrass. Fenoxaprop-ethyl (Acclaim extra) is one option for postemergence crabgrass control in cool season turf. Another option in turf is quinclorac (Drive) which has good safety on new spring seeded stands. In landscape beds several postemergence herbicides provide crabgrass control and can be used over the top of most ornamentals (other than ornamental grasses). This includes sethoxidim (Vantage), fluazifop-P-butyl (Ornamec, Fusilade II), and clethodim (Envoy plus).

Gordon Johnson, Extension Horticulture Agent, UD, Kent County

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